Hexahydrotriazine compounds and insecticides

ABSTRACT

Hexahydrotriazine compounds of the formula:  
                 
 
     are prepared by reacting a compound of the formula:  
                 
 
     with a di(monohalomethyl)amine compound or a primary amine compound in combination with formalin or paraformaldehyde, or by reacting a hexahydrotriazine derivative with a compound of the formula: R 2 CH 2 —Y—.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to hexahydrotriazine compounds, aprocess for preparing the same and insecticides containing the same asactive ingredients. The hexahydrotriazine compounds provided by thisinvention are represented by the following general formula (I):

[0003] wherein R stands for lower alkyl or lower alkenyl; R₁ stands forhydrogen, lower alkyl, lower alkenyl, lower alkynyl or a group indicatedby

[0004] and R₂ stands for a group indicated by

[0005] 2. Prior Art

[0006] A variety of chemicals have been developed and used asinsecticides for controlling harmful insects. Representative examples ofsuch chemicals are organic phosphorous compounds, carbamate compoundsand synthetic pyrethroids. However, by the repeated use of theseinsecticides, many harmful insects have acquired resistance to thesechemicals, thus making it difficult to control such insects. On theother hand, although some conventional insecticides have highinsecticidal activity, they might cause environmental pollution problemseither due to their high toxicity to warm-blooded animals or fishes andCrustacea or due to their remaining in the environment in large amountsfor a long time after use, thus putting the ecological system out oforder. Accordingly, there is a demand for the development of novelinsecticides which more effectively control harmful insects, which haveacquired resistance to conventional chemicals, and yet are low intoxicity not only to warm-blooded animals but also fishes and Crustacea.There is also a demand for novel insecticides which remain in plants andsoils in decreased amounts after their use, and do not producephytotoxicity in various plants.

OBJECTS AND SUMMARY OF THE INVENTION

[0007] An object of this invention is to provide novel compounds which(1) more effectively control harmful insects that have acquiredresistance to conventional chemicals, (2) are low in toxicity not onlyto warm-blooded animals but also fishes and Crustacea and (3) remain indecreased amounts in plants and soils after their use. Lastly, suchnovel compounds do not produce phytotoxicity in various plants.

[0008] Another object of this invention is to provide a process forpreparing such compounds.

[0009] A further object of this invention is to provide improvedinsecticides which (1) more effectively control harmful insects havingresistance to conventional insecticides, (2) are low in toxicity notonly to warm-blooded animals but also fishes and Crustacea, and (3)remain in decreased amounts in plants and soils after their use. Lastly,such improved insecticides do not produce phytotoxicity in variousplants.

[0010] Through research toward the development of various novelhexahydrotriazine compounds, we have found that the hexahydrotriazinecompounds represented by the following general formula (I):

[0011] wherein R stands for lower alkyl or lower alkenyl; R₁ stands forhydrogen, lower alkyl, lower alkenyl, lower alkynyl or a group indicatedby

[0012] and R₂ stands for a group indicated by

[0013] can be used as extremely powerful insecticides which exhibitrapid effects. The present invention has been developed on the basis ofthis finding.

[0014] Further objects, features and advantages of the present inventionwill become aparent from the Detailed Description of the PreferredEmbodiments which follows, when considered together with theillustrative examples.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The compounds of this invention represented by the generalformula (I) are novel compounds which have not been described in anyprior publication and were synthesized by us for the first time. Thesecompounds may be prepared by the processes described below.

[0016] wherein R stands for lower alkyl or lower alkenyl; R₁ stands forhydrogen, lower alkyl, lower alkenyl, lower-alkynyl or a group indicatedby

[0017] R₂ stands for a group indicated by

[0018] and X stands for halogen.

[0019] In the preparation process (a), as indicated by the reactionformula set forth above, the compounds of this invention may be readilyprepared by reacting, in a solvent, a compound represented by thegeneral formula (II); with a compound represented by the general formula(III), such as bis(chloromethyl)methylamine, bis(chloromethyl)ethylamineand bis(chloromethyl)propylamine, in the presence of a basic material.

[0020] Examples of the suitable solvents which may be used in thisreaction are; ethers such as diethyl ether and tetrahydrofuran;acetonitrile; aromatic hydrocarbons; chlorinated hydrocarbons; DMF; andDMSO. These solvents may be used alone or in combination. Compoundswhich may be used as the basic materials are, for example, inorganicbases such as sodium hydroxide and potassium carbonate, and organicbases such as pyridine and triethylamine. These bases may be used inexcess and particularly, 2.1 to 4 mols per 1 mol of the compound (II)are preferable.

[0021] The reaction temperature may be freely set within a range of from−20° C. to 100° C., preferably from −5° C. to 10° C.

[0022] wherein R, R₁ and R₂ have the same meanings defined above.

[0023] In the preparation process (b) as indicated by the reactionformula set forth above, the compounds of this invention may be readilyprepared by reacting a compound represented by the general formula (II)with a primary amine, represented by the general formula R—NH₂ (IV)wherein R has the same meaning defined above, such as methyl amine,ethyl amine and allyl amine and a 37% formalin solution orparaformaldehyde, in a solvent.

[0024] Examples of the suitable solvents which may be used in thisreaction are: alcohols such as methanol and ethanol; ethers such asdioxane and tetrahydrofuran; and water. These solvents may be used aloneor in combination. The reaction temperature may be freely set within arange from a room temperature to a boiling temperature of a solventused, preferably from 50° C. to 100° C.

[0025] wherein R, R₁ and R₂ have the same meanings defined above and Ystands for halogen or a group indicated by —OSO₂CH₃ or

[0026] In the preparation process (c), as indicated by the reactionformula set forth above, the compounds of this invention may be readilyprepared by reacting a compound represented by the general formula (V)with a compound represented by the general formula (VI) in the presenceof a basic material in an inert solvent.

[0027] Examples of the suitable solvents which may be used in thisreaction are: DMF; DMSO; acetonitrile; and ethers, such astetrahydrofuran and dioxane. These solvents may be used alone or incombination. Compounds which may be used as the basic materials are forexample, sodium hydride, potassium carbonate, sodium hydroxide etc. 1.1to 2.5 mols of these bases per 1 mol of the compound (V) are preferablyused. The reaction temperature may be freely set within a range from aroom temperature to 150° C., preferably from 40° C. to 100° C.

[0028] Hexahydrotriazine compounds of this invention are novelcompounds. Typical compounds of this invention are set forth in thefollowing Table 1. TABLE 1

Compound No. R₂ R₁ R Melting Point 1

H CH₃ 150˜154° C. 2 ″ ″ C₂H₅ 124˜125° C. 3 ″ ″ iC₃H₂ 121˜122° C. 4 ″ ″—CH₂CH═CH₂ 108˜109° C. 5 ″ CH₃ CH₃ 116˜117° C. 6

″ ″ 125˜126° C. 7

C₂H₅ ″ 163˜164° C. 8 ″ nC₃H₂ ″ 102˜104° C. 9

nC₃H₇ CH₃ 139˜143° C. 10 

—CH₂CH═CH₂ ″ 112˜114° C. 11  ″ —CH₂C≡CH ″ 124˜125° C. 12  ″

″ 188˜189° C. (decomp.)

[0029] An effective amount of any of the compounds of this invention maybe applied directly as an insecticide or may be formulated byconventional technology in the form of an emulsion, a wettable powder, adust, a granule or in a flowable form, and then applied as a formulatedproduct. A liquid or solid carrier may be used for preparing aformulated product containing one or more of the compounds of thisinvention. Liquid carriers which may be used for this purpose include,for example, organic solvents, and conveniently used are xylene,chlorobenzene, methylnaphthalene, cyclohexanone, isophorone, alcohols,dimethylformamide and N-methylpyrrolidone. Examples of solid carriersinclude kaoline, talc, bentonite, diatomaceous earth and clay, andsynthetic compounds such as alumina, zeolite and silicates may also beused. In preparation of the formulated products, various adjuvants, suchas emulsifiers, dispersants, spreaders, wetting agents and penetratingagents, may be used for providing the products with the desiredproperties of emulsification, dispersion, suspension and penetration.

[0030] The compounds of this invention, which are represented by thegeneral formula (I) set forth above, have strong insecticidal activityagainst various harmful insects, including Hemiptera, Lepidoptera,Coleoptera, Diptera, Orthoptera and Isoptera, and yet are low intoxicity to human beings and animals and do not produce phytotoxicity invarious plants, and thus can be practically used as superiorinsecticides.

[0031] Examples of harmful insects which may be effectively controlledby the compounds of this invention are as follows:

[0032] Hemiptera such as Nilaparvata lugens, Laodelphax striatellus,Nephotettix cincticeps, Pseudococcus comstocki, Unaspis yanonensis,Myzus persicae, Aphis gossypii, Lipaphis erysimi, Stephanitis nashi,Scotinophara lurida and Trialeurodes vaporariorus; Lepidoptera such asPieris rapae, Spodoptera litura, Mamestra brassicae, Chilo suppressalis,Plutera xylostella, Adoxophyes orana, Agrotis segetum, Cnaphalocrocismedinalis and Ostrinia furnacalis; Coleoptera such as Henosepilachnavigintioctopunctata, Aulacophora femoralis, Phyllotreta striolata,Lissorhoptrus oryzophilus, Sitophilus zeamais and Anomala rufocuprea;Diptera such as Musca domestica, Hylemia platura, Culex pipiens;Orthoptera such as Gryllotalpa africana, Blatella germanica and Locustamigratoria; and Isoptera such as Coptotermes formosanus andReticulitermes speratus.

[0033] The present invention will now further be explained by way of thefollowing non-limiting examples.

EXAMPLES

[0034] The processes for the preparation of the compounds of thisinvention are described in detail in the following Synthesis Examples.

Synthesis Example 1 Synthesis of1-(2-chloro-5-pyridylmethyl)-5-methyl-2-nitroiminohexahydro-1,3,5-triazine

[0035] 0.6 g of 1-(2-chloro-5-pyridylmethyl)-3-nitroguanidine and 0.4 gof bis(chloromethyl)methylamine were suspended in dried THF. To thesuspension, a solution of 0.52 g of triethylamine in THF was addeddropwise with cooling. The reaction mixture was stirred for 1 hour, andthen poured into ice water. The mixture was extracted withdichloromethane. After the extract was dried over anhydrous magnesiumsulfate, dichloromethane was distilled off. The residue wasrecrystallized from methanol to obtain 0.78 g of the title compound.This compound is No. 1 in Table 1. m.p.: 150-154° C.

Synthesis Example 2 Synthesis of1-(2-chloro-5-pyridylmethyl)-5-ethyl-2-nitroiminohexahydro-1,3,5-triazine

[0036] To a stirring mixture of 1 g of1-(2-chloro-5-pyridylmethyl)-3-nitroguanidine, 0.28 g of 70% ethylaminein water and 20 ml of ethanol, 0.71 g of 37% formalin solution was addeddropwise with heating. The reaction mixture was heated under reflux fortwo hours. After being allowed to cool to room temperature, the crystalsformed, which were filtrated off and recrystallized from methanol toobtain 1.15 g of the title compound. This compound is No. 2 in Table 1.m.p.: 124-125° C.

Synthesis Example 3 Synthesis of1-(2-chloro-5-pyridylmethyl)-3,5-dimethyl-2-nitroiminohexahydro-1,3,5-triazine

[0037] 1 g of 1,5-dimethyl-2-nitroiminohexahydro-1,3,5-triazine wasdissolved in 20 ml of dried DMF. To the solution, 0.27 g of 60% sodiumhydride was added with cooling. The mixture was stirred for 1 hour atroom temperature until evolution of hydrogen was ceased and then themixture was heated with stirring further for 1 hour at 50° C. To themixture, a solution of 0.9 g of 2-chloro-5-pyridylmethylchloride in 8 mlof dried DMF was added dropwise at 40-50° C. After this addition, thereaction mixture was heated with stirring it for two hours at 70-80° C.The mixture was poured into ice-water and extracted withdichloromethane. The extract was dried over anhydrous magnesium sulfate,and dichloromethane was distilled off. The residue was purified by acolumn chromatography to obtain 1.3 g of the title compound. Thiscompound is No.5 in Table 1. m.p.: 116-117° C.

Synthesis Example 4 Synthesis of1-(2-chloro-5-thiazolylmethyl)-3,5-dimethyl-2-nitroiminohexahydro-1,3,5-triazine

[0038] 1.7 g of 1,5-dimethyl-2-nitroiminohexahydro-1,3,5-triazine wasdissolved in 20 ml of dried DMF. To the solution, 0.28 g of 60% sodiumhydride was added portionwise with cooling. The mixture was stirred for1 hour at room temperature until evolution of hydrogen was ceased andthen the mixture was heated with stirring further for 1 hour at 50° C.To the mixture, a solution of 1.7 g of2-chloro-5-thiazolylmethylchloride in 8 ml of dried DMF was addeddropwise at 40-50° C. After this addition, the reaction mixture washeated with stirring for two hours at 70-80° C. The mixture was pouredinto ice-water and extracted with dichloromethane. The extract was driedover anhydrous magnesium sulfate, and dichloromethane was distilled off.The residue was purified by a column chromatography to obtain 0.82 g ofthe title compound. This compound is No.6 in Table 1. m.p.: 125-126° C.

[0039] Some specific Formulation Examples are shown below. However, itis noted that the carriers, surfactants and other additives which may beused in formulation of the insecticides according to this invention arenot limited by the following Formulation Examples. In the followingFormulation Examples, “part” stands for “part by weight”.

Formulation Example 1

[0040] 32.5 Parts of the Compound No.1 in Table 1, 3 parts of ligninsulfonic acid, 4 parts of polyoxyethylene alkylphenyl ether, 2 parts ofsilicon dioxide hydrate and 58.5 parts of clay are well mixed whilebeing powdered to obtain a wettable powder.

Formulation Example 2

[0041] 5.4 Parts of the Compound No. 2 in Table 1, 2 parts of silicondioxide hydrate and 92.6 parts of talc are well mixed while beingpowdered to obtain a dust.

Formulation Example 3

[0042] 5.4 Parts of the Compound No. 3 in Table 1, 3 parts of ligninsulfonate, 1 part of sodium dodecylbenzenesulfonate, 30 parts ofbentonite and 60.6 parts of clay are well mixed while being powdered.The mixture is then kneaded with water, granulated and dried to obtaingranules.

[0043] The insecticidal effects of the compounds of this invention areshown by referring to some Test Examples.

Test Example 1

[0044] Five rice seedlings having a height of about 7 cm were dipped,for 10 seconds, into aqueous dilutions of wettable powder eachcontaining a predetermined concentration of each sample compound,prepared in accordance with the procedure as described in FormulationExample 1. After air drying, the roots of the five rice seedlings werewrapped with sanitary cotton dampened with water, and placed in a glasscylinder having a diameter of 3 cm and a height of 20 cm. Ten secondinstar larvae of a green rice leafhopper which had acquired resistanceto chemicals were released into each glass cylinder. The cylinder wasallowed to stand in a room maintained at 26° C. The mortality of thelarvae was examined 48 hours after treatment. The results are shown inTable 2. TABLE 2 Compound No. Mortality (%), 500 ppm 1 100 2 100 3 100 4100 5 100 6 100 7 100 8 100 9 100 10  100 11  100 12  100 Comparative 70 Compound

[0045]

Test Example 2

[0046] Five rice seedlings having a height of about 7 cm were dipped,for 10 seconds, into aqueous dilutions of wettable powder eachcontaining a predetermined concentration of each sample compound,prepared in accordance with the procedure as described in FormulationExample 1. After air drying, the roots of the five rice seedlings werewrapped with sanitary cotton dampened with water, and placed in a glasscylinder having a diameter of 3 cm and a height of 20 cm. Ten secondinstar larvae of a brown rice planthopper which had acquired resistanceto chemicals were released into each glass cylinder. The cylinder wasallowed to stand in a room maintained at 26° C. The mortality of thelarvae was examined 48 hours after treatment. The results are shown inTable 3. TABLE 3 Compound No. Mortality (%), 500 ppm 1 100 2 100 3 100 4100 5 100 6 100 7 100 8 100 9 100 10  100 11  100 12  100 Comparative 65 Compound

[0047] Note: The comparative compound set forth in Table 3 is the sameas that in Table 2.

[0048] As will be apparent from the foregoing, the compounds of thisinvention are extremely active for controlling various harmful insectsand yet are low in toxicity to warm-blooded animals, fishes andCrustacea, the remaining quantity thereof after their use is small, andthey do not produce phytotoxicity in various plants.

We claim:
 1. A hexahydrotriazine compound represented by the followinggeneral formula (I):

wherein R stands for lower alkyl or lower alkenyl; R₁ stands forhydrogen, lower alkyl, lower alkenyl, lower alkynyl or a group indicatedby

and R₂ stands for a group indicated by


2. The hexahydrotriazine compound according to claim 1 which is1-(2-chloro-5-pyridylmethyl)-5-methyl-2-nitroiminohexahydro-1,3,5-triazine.3. The hexahydrotriazine compound according to claim 1 which is1-(2-chloro-5-pyridylmethyl)-5-ethyl-2-nitroiminohexahydro-1,3,5-triazine.4. The hexahydrotriazine compound according to claim 1 which is1-(2-chloro-5-pyridylmethyl)-5-isopropyl-2-nitroiminohexahydro-1,3,5-triazine.5. The hexahydrotriazine compound according to claim 1 which is 1-(2-chloro-5-pyridylmethyl )-5-allyl-2-nitroiminohexahydro-1,3,5-triazine.6. The hexahydrotriazine compound according to claim 1 which is1-(2-chloro-5-pyridylmethyl)-3,5-dimethyl-2-nitroiminohexahydro-1,3,5-triazine.
 7. Thehexahydrotriazine compound according to claim 1 which is1-(2-chloro-5-thiazolylmethyl)-3,5-dimethyl-2-nitroiminohexahydro-1,3,5-triazine.8. The hexahydrotriazine compound according to claim 1 which is1-(2-chloro-5-pyridylmethyl)-3-ethyl-5-methyl-2-nitroiminohexahydro-1,3,5-triazine.9. The hexahydrotriazine compound according to claim 1 which is1-(2-chloro-5-pyridylmethyl)-3-propyl-5-methyl-2-nitroiminohexahydro-1,3,5-triazine.10. The hexahydrotriazine compound according to claim 1 which is1-(2-chloro-5-thiazolylmethyl)-3-propyl-5-methyl-2-nitroiminohexahydro-1,3,5-triazine.11. The hexahydrotriazine compound according to claim 1 which is1-(2-chloro-5-pyridylmethyl)-3-allyl-5-methyl-2-nitroiminohexahydro-1,3,5-triazine.12. The hexahydrotriazine compound according to claim 1 which is1-(2-chloro-5-pyridylmethyl)-3-propargyl-5-methyl-2-nitroiminohexahydro-1,3,5-triazine.13. The hexahydrotriazine compound according to claim 1 which is1,3-bis(2-chloro-5-pyridylmethyl)-2-nitroiminohexahydro-1,3,5-triazine.14. A process for preparing a hexahydrotriazine compound represented bythe following general formula (I):

wherein R stands for lower alkyl or lower alkenyl; R₁ stands forhydrogen, lower alkyl, lower alkenyl, lower alkynyl or a group indicatedby

and R₂ Stands for a group indicated by

or

comprising the step of reacting a compound represented by the generalformula (II):

wherein R₁ and R₂ have the same meanings defined above, with a compoundrepresented by the general formula (III) R—N(CH₂X)₂  (III) wherein R hasthe same meaning defined above and X stands for halogen.
 15. A processfor preparing a hexahydrotriazine compound represented by the followinggeneral formula (I):

wherein R stands for lower alkyl or lower alkenyl; R₁ stands forhydrogen, lower alkyl, lower alkenyl, lower alkynyl or a group indicatedby

and R₂ stands for a group indicated by

or

comprising the step of reacting a compound represented by the generalformula (II):

wherein R₁ and R₂ have the same meanings defined above, with a primaryamine represented by the general formula (IV): R—NH₂ wherein R has thesame meaning defined above, and formalin or paraformaldehyde.
 16. Aprocess for preparing a hexahydrotriazine compound represented by thefollowing general formula (I):

wherein R stands for lower alkyl or lower alkenyl; R₁ stands forhydrogen, lower alkyl, lower alkenyl, lower alkynyl or a group indicatedby

and R₂ stands for a group indicated by

or

comprising the step of reacting a compound represented by the generalformula (V):

wherein R and R₁ have the same meanings defined above, with a compoundrepresented by the general formula (VI): R₂CH₂—Y  (VI) wherein R₂ hasthe same meaning defined above and Y stands for halogen or a groupindicated by —OSO₂CH₃ or


17. An insecticide containing a suitable carrier, and, as an activeingredient, a hexahydrotriazine compound represented by the followinggeneral formula (I):

wherein R stands for lower alkyl or lower alkenyl; R₁ stands forhydrogen, lower alkyl, lower alkenyl, lower alkynyl or a group indicatedby

and R₂ stands for a group indicated by


18. The insecticide according to claim 17 wherein the compound is1-(2-chloro-5-pyridylmethyl)-5-methyl-2-nitroiminohexahydro-1,3,5-triazine.19. The insecticide according to claim 17 wherein the compound is1-(2-chloro-5-pyridylmethyl)-5-ethyl-2-nitroiminohexahydro-1,3,5-triazine.20. The insecticide according to claim 17 wherein the compound is1-(2-chloro-5-pyridylmethyl)-5-isopropyl-2-nitroiminohexahydro-1,3,5-triazine.21. The insecticide according to claim 17 wherein the compound is1-(2-chloro-5-pyridylmethyl)-5-allyl-2-nitroiminohexahydro-1,3,5-triazine.22. The insecticide according to claim 17 wherein the compound is1-(2-chloro-5-pyridylmethyl)-3,5-dimethyl-2-nitroiminohexahydro-1,3,5-triazine.23. The insecticide according to claim 17 wherein the compound is1-(2-chloro-5-thiazolylmethyl)-3,5-dimethyl-2-nitroiminohexahydro-1,3,5-triazine.24. The insecticide according to claim 17 wherein the compound is1-(2-chloro-5-pyridylmethyl)-3-ethyl-5-methyl-2-nitroiminohexahydro-1,3,5-triazine.25. The insecticide according to claim 17 wherein the compound is1-(2-chloro-5-pyridylmethyl)-3-propyl-5-methyl-2-nitroiminohexahydro-1,3,5-triazine.
 26. Theinsecticide according to claim 17 wherein the compound is1-(2-chloro-5-thiazolylmethyl)-3-propyl-5-methyl-2-nitroiminohexahydro-1,3,5-triazine.27. The insecticide according to claim 17 wherein the compound is1-(2-chloro-5-pyridylmethyl)-3-allyl-5-methyl-2-nitroiminohexahydro-1,3,5-triazine.28. The insecticide according to claim 17 wherein the compound is1-(2-chloro-5-pyridylmethyl)-3-propargyl-5-methyl-2-nitroiminohexahydro-1,3,5-triazine.29. The insecticide according to claim 17 wherein the compound is1,3-bis(2-chloro-5-pyridylmethyl)-2-nitroiminohexahydro-1,3,5-triazine.